1. Field of the Invention
The present invention relates to a honeycomb structure, more preferably to a honeycomb structure having a volume resistivity within a predetermined range and electrode portions capable of being formed easily and further functioning as a heater, while serving as a catalyst carrier.
2. Description of Related Art
There has conventionally been used a cordierite honeycomb structure where a catalyst is loaded for treating harmful substances in exhaust gas discharged from an automobile engine. It is also known that a honeycomb structure formed of a silicon carbide based sintered body is used for purifying exhaust gas (see, e.g., Patent Document 1).
In the case of treating exhaust gas by a catalyst loaded on a honeycomb structure, it is necessary to raise the temperature of the catalyst up to a predetermined level. However, there is a problem of insufficient purification of exhaust gas at the time of engine starting because the temperature of the catalyst is low.
Therefore, there is investigated a method where the temperature of exhaust gas is raised with a metal heater disposed on the upstream side of a honeycomb structure having a catalyst loaded thereon (see, e.g., Patent Document 2).